HR: 11:50h
AN: GP22A-07    [Abstracts]
TI: The FORC Method: Where we are and where we are going.
AU: * Verosub, K L
EM: verosub@geology.ucdavis.edu
AF: Geology Department, University of California, Davis, CA 95616 United States
AU: Acton, G
EM: acton@geology.ucdavis.edu
AF: Geology Department, University of California, Davis, CA 95616 United States
AU: Roth, A
EM: alroth@ucdavis.edu
AF: Geology Department, University of California, Davis, CA 95616 United States
AB: In the seven years since its development, the FORC method has evolved into a powerful new technique for probing the microscopic mechanisms of magnetic behavior. The original motivation for development of the method was to obtain more detailed information about the magnetic mineralogy and magnetic grain-size distribution of natural geologic samples consisting of magnetite, maghemite and/or hematite. In recent years, the method has also proven to be useful for identifying other magnetic minerals, such as greigite, goethite, and siderite, as well as for unraveling more complex magnetic systems, such as intergrowths of magnetic exsolution lamellae. The FORC method has also been successfully used in studies of the progressive transformation of magnetic minerals at both low temperatures, i.e. pedogenesis and sulfate reduction, and at high temperatures, i.e. hydrothermal and geothermal alteration. Additional advances can be expected with the availability of instruments that can acquire FORC data at both low and high temperatures. For example, the ability to acquire FORC data at high temperatures holds the promise of a major advancement in the both the rate and reliability with which absolute paleointensity determinations can be made. Progress has also been made in developing new theoretical models for the interpretation of FORC diagrams and in establishing a better understanding of the relationship between FORC diagrams and Preisach diagrams. The FORC method is also being used to study the magnetic properties of advanced magnetic media, condensed matter systems, magnetic nanostructures and atmospheric aerosols. In turn, these applications are leading to new methods for representing FORC diagrams and for quantifying and interpreting the information that they contain. The development and availability of standardized computer programs for processing, displaying and analyzing FORC data is further contributing to development of the method.
DE: 1512 Environmental magnetism
DE: 1533 Remagnetization
DE: 1540 Rock and mineral magnetism
DE: 1594 Instruments and techniques
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2004 AGU Fall Meeting